# Intro01

1. Mnemonics

The left side of the page shows an actual computer session with the
result of each sentence shown at the left margin.
First cover the comments at the right,
and then attempt to state in English the meaning of each primitive
so as to make clear the relations between related symbols.
For example, “< is less than
and <. is lesser of (that is, minimum)”.

```   7<5                        Less than
0                             A zero is interpreted as false.
7<.5                       Lesser of
5
7>5                        Greater than
1                             A one is true (à la George Boole)
7>.5                       Greater of
7
10^3                       Power (à la Augustus De Morgan)
1000
10^.1000                   Logarithm
3
7=5                        Equals
0
b=: 5                      Is (assignment or copula)
7<.b
5
Min=: <.                   Min is <.
power=: ^                  power is ^
gt=: >                     gt is >
10 power (5 Min 3)
1000
```

Exercises

1.1   Enter the following sentences on the computer,
observe the results, give suitable names to any new primitives
(such as * and +. and *.),
and comment on their behaviour.

```   a=:0 1 2 3
b=:3 2 1 0
a+b
a*b
a-b
a%b
a^b
a^.b
a<b
a>b
(a<b)+(a>b)
(a<b)+.(a>b)
```